What is a resonator guitar?

A resonator guitar (aka resophonic guitar) is an acoustic guitar with one or more metal resonator discs mounted inside the body. A resonator guitar produces sound by carrying string vibrations through the bridge to one or more spun metal cones (aka resonators), instead of to the sound board (the top or front of an acoustic guitar) as with a typical acoustic guitar.

Resonator guitars were designed to be louder than existing acoustic guitars, which were often overwhelmed by louder instruments in live performances. Resonator guitars were soon sought out for their distinctive sound and became the norm in musical styles such as old-time music, bluegrass, and others.

What is the difference between a resonator guitar and a dobro?

There is some confusing terminology to explain before we get to the main resonator guitar styles and designs. So far we’ve used the term resonator, but some call them dobros, while others consider only square-neck resonators to be dobros. While the term dobro has historically been used to refer to these instruments, it can also be confusing since “Dobro™” is also a trademark name for a family of Gibson resonator guitars. The name dobro was derived from its inventors, the Dopyera Brothers (DoBro), back in the 1920s. Gibson acquired the rights to the name in 1994 when they began producing their own line.

Resonator guitar styles

There are two main styles of resonator guitars based on the manner in which they are played:

Square-necked guitars: A square-neck resonator is laid flat on your lap. These have a special nut that raises the strings high above the fretboard and are typically played with a special slide generically called a Stevens Steel.

Round-necked guitars: The round-neck type of resonator is held and played in the manner of a regular guitar; this basically has an ordinary guitar neck.

Resonator guitar designs

There are three main designs:

The tricone (three metal cones)

The single cone “biscuit” design

The single inverted-cone design (aka spider bridge) of Dobro-brand instruments and instruments that copy the Dobro design

Origin of the Dobro

In 1925, John Dopyera was asked by George Beauchamp to create a louder guitar. Beauchamp was an industrious musician and promoter of vaudeville shows, vaudeville being a theatrical genre of variety entertainment which was most popular in North America from the early 1880s until the early 1930s. Beauchamp’s goal was to have a louder acoustic guitar, one that could be heard over the other orchestral instruments being played in the vaudeville shows.

So John Dopyera invented a guitar with three aluminum cones known as resonators (similar to diaphragms inside a speaker) mounted beneath the bridge. This resonator guitar turned out to be much louder than the regular acoustic guitar. The tone of the guitar was rich and metallic. Dopyera and his brothers Rudy and Emil, as well as other investors, founded the National String Instrument Corporation to manufacture the new type of “resophonic” guitar, which was sold mainly to musicians working in cinemas and jazz clubs in the USA. After several years, the three brothers left the corporation and started a new company, Dobro (the name they also gave to the instrument), a play on words derived from the “Do” in Dopyera and “bro” from Brothers, and a word which means “good” in Slovak. Their slogan was: Dobro means good in any language!.